DE102019114191A1 - Laser processing device and method for the simultaneous and selective processing of a plurality of processing points on a workpiece - Google Patents

Abstract

The present invention relates to a laser processing device and a method for processing processing points on a workpiece. The laser processing device comprises a. a laser radiation source (3) which is set up to generate a laser beam (10) and to emit it along an optical path (4) in the direction of the workpiece (2); b. a beam splitting unit (5) arranged downstream of the laser radiation source (3) in the beam direction, which is set up to split the laser beam (10) into a plurality of partial beams (T) which are distributed in a predetermined spatial pattern; c. a beam selection unit (6) which is arranged downstream of the beam splitting unit (5) and is set up to • forward a first number (A1) of the partial beams (T) along the optical path (4) in the direction of the workpiece (2), • a second Number (A2) of the partial beams (T) to deflect from the optical path (4), wherein the beam selection unit (6) is also set up to select partial beams (T) from the spatial pattern of the partial beams (T) in any spatial combination and the assign the first number (A1) and the second number (A2); d. a beam positioning unit (9) arranged downstream of the beam selection unit (6) in the beam direction, which is set up to image laser spots (18) corresponding to the first number (A1) of partial beams (T) on the workpiece (2), and is also set up to: to move the laser spots (18) over the workpiece (2) simultaneously and synchronously for positioning and / or processing.

Description

The present invention relates to a laser processing device and a method for processing processing points on a workpiece. The processing points can be, for example, defects in a workpiece that are subjected to a repair or correction carried out by means of laser processing. In this context, the workpieces mentioned can be displays or display surfaces, for example. Furthermore, the laser processing device proposed by the invention or the method proposed by the invention for processing a workpiece by way of a “Laser Induced Forward Transfer” (LIFT for short) process can be used, that is to say for processing predetermined processing points on a workpiece.

During the production of graphic displays such as displays, OLED (organic light emitting diode) displays or mini LED displays, for example, production-related defects can occur. Such defects are to be understood as “processing points” in the context of the terminology used here. These flaws can occur on certain pixels of the display, for example in the electrical contact. Undesired deviations with regard to the surface structure (for example homogeneity, layer thickness, planarity, etc.) can be present in those defect areas. An organic light-emitting diode (OLED) is a luminous thin-film component made of organic semiconducting materials, which differs from the so-called inorganic light-emitting diodes (LED) in particular in that the electrical current and luminance is lower and no single-crystal materials are required. Displays based on OLEDs are installed in smartphones, tablet computers, televisions or computer monitors, among other things. The present invention can be used both for processing OLED displays and for processing LED displays (e.g. mini LED displays).

Since such flaws are usually not distributed homogeneously on the display surface and often occur on a large number of display pixels, it is desirable to subject the flaws to a repair or correction process that on the one hand enables several flaws to be processed simultaneously, and on the other hand flexibly can be adapted to a distribution of defects present on a specific display. Laser processing techniques are particularly suitable for such a correction of defects, because such techniques ensure pixel-by-pixel, high-resolution and, at the same time, fast (ablative) processing. Processing such defects with individual laser beams is generally known from the prior art, but is associated with disadvantages in terms of process management and process duration. Correspondingly, methods that allow several defects to be processed in parallel are of particular interest. From the US 9,592,570 B2 Parallel processing provided via beam selection is known, but only that individual spot rows or columns can be selected.

It should be expressly emphasized at this point that the present invention is not only suitable for processing or repairing defects in a display; in principle, any workpieces or materials afflicted with defects can be processed with the laser processing device according to the invention or with the associated method that has a Allow ablative processing. The processed material must therefore be ablatable by laser radiation. Furthermore, the present invention is suitable for use in the LIFT method already mentioned above. Pulsed laser beams (e.g. in point-and-shoot mode) are directed onto a coated substrate in order to transfer material in the direction of the laser radiation onto a second substrate. LIFT processes can be used for the production of thermoelectric transfer materials, polymers and for printing on substrates. Correspondingly, within the scope of the invention, the “processing points” can also be understood as those points on a first substrate (a workpiece in the sense of the invention) at which a material transfer by way of the LIFT method to a second (for example co-planar to the first substrate ) arranged substrate is to take place, in particular around those points of a first substrate (workpiece) which are to be irradiated with laser beams. Depending on the requirements placed on the workpiece to be processed, the LIFT method can be used to create a specified processing pattern (transfer pattern) at defined processing points or pixels on a workpiece. In the context of the present invention, partial beams of a split laser beam can be directed in the point-and-shoot mode onto predetermined processing points on a workpiece.

Due to the continuously advancing development of laser technology, it has been known for many years to use lasers for processing a wide variety of materials, for example in the field of manufacturing electronic components or display elements.

When processing materials with laser radiation (for example laser ablation, laser welding, laser soldering, laser cleaning, laser drilling, laser sintering or laser melting), laser radiation is currently mostly used with a Gaussian intensity distribution used. For many of these processes, however, it is advantageous to adapt the intensity distribution in the machining area of the workpiece to the specific machining process or the material to be machined. Therefore, optimizations of the laser process by changing the intensity distribution in the processing plane are increasingly being investigated. To adapt the intensity distribution, it is known to subject the laser radiation generated by a laser radiation source to beam shaping, which offers considerable optimization potential for the development of the laser process. The resulting advantages of beam shaping are, for example, higher process speeds or better processing results.

As already mentioned, the laser radiation generated by a laser radiation source typically has a Gaussian intensity distribution or a Gaussian beam profile in relation to its beam cross section. Using suitable beam shaping techniques, however, laser beams can be shaped while changing the intensity distribution. Either its phase, its amplitude or both quantities can be modulated together to form an intensity distribution of a laser beam. Phase modulators, amplitude modulators or phase and amplitude modulators are used accordingly, for example in the form of diffractive beam shapers. Diffractive beam formers (Diffractive Optical Elements, DOE for short) for setting far-field intensities can be produced as phase elements in glass or other transparent materials.

Furthermore, the form of an intensity distribution can take place by refraction and reflection on optical elements. Correspondingly shaped refractive or reflective elements such as deformed or deformable mirrors or transmissive elements with a geometric deformation of the surface or shape are used. The individual partial beams of a laser beam incident on the refractive or reflective optical element fall on differently curved surfaces and are reflected or refracted on them. The totality of the partial beams forms a new intensity distribution after being formed by the element. An example of such a beam shaping is the shaping of a Gaussian-shaped laser beam into a top-hat shaped laser beam, also called a Gauss-to-top-hat beam shaper. Such a beam shaper can also be used in the laser processing device according to the invention. The geometrical deformation of the surface necessary for beam shaping can be calculated using analytical, numerical or iterative methods (e.g. superposition of Zernike polynomials).

Diffractive beam-shaping elements can, however, also be designed as beam splitters (within the scope of the present invention, the function of the DOE as a beam splitter is decisive). Binary grids or blazed gratings may be mentioned as examples in this context. Due to the geometry of the diffractive structure, constructive interference occurs on a rectangular grid in the spatial frequency space (k-space). A wide variety of arrangements of active diffraction orders (constructive interference) can be implemented using numerical algorithms. The angular separation of the diffraction orders must be large enough in relation to the far field divergence of the incident laser radiation, since otherwise interference disturbs the arrangement of the active diffraction orders.

Such unchangeable DOEs are increasingly being replaced by programmable modulation units for dynamic shaping of the laser radiation. With programmable modulation units, the spatial and temporal intensity distribution of the laser radiation emitted by a laser radiation source can be adjusted. Such programmable modulation units are also referred to as “spatial light modulators (SLM)”. Spatial light modulators can also be used for beam splitting.

A wide variety of laser radiation sources can be used in laser processing. For precise material removal, the aim should be as small a focus as possible with a laser with as short a wave as possible. In the course of the development of more powerful and long-lasting laser radiation sources for the UV range, CO ₂ lasers are only used relatively rarely. Excimer lasers are also rarely used these days. However, UV nanosecond lasers are used as standard. For efficient material processing, laser radiation must be used with a wavelength that is absorbed by the material to be removed from the workpiece to be processed. Laser radiation with wavelengths in the near-infrared and VIS range are less suitable for this unless short pulse durations in the picosecond and femtosecond range are used.

So-called solid-state lasers, in particular Nd: YAG lasers, are often used for laser processing, for example. These lasers can be tailored precisely to the respective application in terms of the achievable pulse duration, pulse energy and wavelength.

In order to increase the processing speed during laser processing, it is known to reflect laser radiation on mirrors and to deflect it onto certain points on a workpiece surface to be processed. An arrangement Several such mirrors can be combined in one structural unit and form a mirror scanner. For example, galvanometrically driven mirror scanners are known, the associated mirrors of which can be rotated by a defined angle by means of a rotary drive. In this way, a laser beam incident on such a mirror can be directed onto different locations on the workpiece.

Based on the foregoing, the object of the present invention is to provide a laser processing device and a method for processing a workpiece (e.g. using the LIFT method) or for correcting imperfections in a workpiece, which enables multiple processing points of the workpiece to be processed quickly and in parallel .

The stated object is achieved with a device with the features of patent claim 1 and a method with the features of patent claim 30.

1. a. eine Laserstrahlungsquelle, die dazu eingerichtet ist, einen Laserstrahl zu erzeugen und entlang eines optischen Pfades in Richtung des Werkstücks auszusenden;
2. b. eine der Laserstrahlungsquelle in Strahlrichtung nachgeordnete Strahlteilungseinheit, die dazu eingerichtet ist, den Laserstrahl in eine Vielzahl von Teilstrahlen aufzuteilen, die in einem vorgegebenen räumlichen Pattern verteilt sind;
3. c. eine der Strahlteilungseinheit in Strahlrichtung nachgeordnete Strahlselektionseinheit, die dazu eingerichtet ist,
   • • eine erste Anzahl der Teilstrahlen entlang des optischen Pfades in Richtung des Werkstücks weiterzuleiten,
   • • eine zweite Anzahl der Teilstrahlen aus dem optischen Pfad abzulenken,
   wobei die Strahlselektionseinheit ferner dazu eingerichtet ist, aus dem räumlichen Pattern der Teilstrahlen in beliebiger räumlicher Kombination Teilstrahlen zu selektieren und der ersten Anzahl und der zweiten Anzahl zuzuordnen;
4. d. eine der Strahlselektionseinheit in Strahlrichtung nachgeordnete Strahlpositionierungseinheit, die dazu eingerichtet ist, zu der ersten Anzahl der Teilstrahlen korrespondierende Laserspots auf dem Werkstück abzubilden, und ferner dazu eingerichtet ist, die Laserspots gegebenenfalls zur Positionierung und/oder zur Bearbeitung simultan und synchron über das Werkstück zu bewegen.

The device on which the invention is based is provided for machining predetermined machining locations on a workpiece. The device comprises

1. a. a laser radiation source which is configured to generate a laser beam and to emit it along an optical path in the direction of the workpiece;
2. b. a beam splitting unit which is arranged downstream of the laser radiation source in the beam direction and which is set up to split the laser beam into a plurality of partial beams which are distributed in a predetermined spatial pattern;
3. c. a beam selection unit arranged downstream of the beam splitting unit in the beam direction, which is set up to
   • • forward a first number of partial beams along the optical path in the direction of the workpiece,
   • • divert a second number of partial beams from the optical path,
   wherein the beam selection unit is further set up to select partial beams from the spatial pattern of the partial beams in any spatial combination and to assign them to the first number and the second number;
4. d. a beam positioning unit downstream of the beam selection unit in the beam direction, which is set up to image laser spots corresponding to the first number of partial beams on the workpiece, and is also set up to move the laser spots simultaneously and synchronously over the workpiece for positioning and / or processing, if necessary .

As in feature d. Coming to the expression, it can be provided to move the laser spots for positioning and for processing simultaneously and synchronously over the workpiece. However, the laser processing device can also easily be used for parallel point-and-shoot processing of several processing points. A positioning or processing movement of the laser spots on the workpiece is therefore not absolutely necessary; a one-time alignment can also be sufficient (depending on the processing task).

With the laser processing device according to the invention, workpieces with a defined or predetermined pattern of imperfections or of points to be processed (e.g. in the LIFT process) can be processed. Accordingly, the general term “processing points” is used below, whereby “processing points” can mean both missing points and other processing points (e.g. the points to be processed in the LIFT procedure). In both cases, the workpiece to be machined can be built up periodically in relation to the workpiece surface, i.e. the surface is made up of pixels distributed in a two-dimensional manner in relation to a two-dimensional plan view. The large number of partial beams provided by the beam splitting unit of the laser machining device initially also provide a periodic arrangement of partial beams. Only with the beam selection unit can the most varied of partial beams be deflected from the optical path, so that any combinations and patterns of partial beams can be passed along the optical path in the direction of the workpiece. In contrast to the prior art described at the beginning, with the present invention not only individual rows or columns of an array of the partial beams can be selected for projection onto the workpiece, but also any geometrical combination. It is not necessary to specify a specific spatial pattern or a number of partial beams; rather, any partial beams belonging to the periodic arrangement of the partial beams (provided via the beam splitting unit) can be selected via the beam selection unit and passed on in the direction of the workpiece.

Depending on the size of the area to be processed, a single positioning of the workpiece relative to the laser processing device may be sufficient, for example in the case in which the area comprising the processing points is smaller than the scan field accessible with the laser processing device, i.e. the area that the Laser spots can be achieved by positioning by means of the beam positioning unit (without relative displacement between the workpiece and the laser processing device). If, on the other hand, the area of the workpiece to be processed is larger than the scan field, it is necessary to calculate a processing path or displacement path related to a relative displacement between the workpiece and the laser processing device. The displacement path can contain a plurality of different machining positions (that is to say relative positions between the workpiece and the laser machining device). The number of processing positions required corresponds to the number of processing steps required. After the workpiece has been positioned relative to the laser processing device (according to one of the processing positions), the number and spatial position of the laser spots or partial beams imaged on the workpiece are determined based on the number and arrangement (i.e. the pattern) of the defects in this processing area. After a first positioning, the partial beams directed onto the workpiece can be adapted to the period on which the partial beams are based (this means the distance between the partial beams) exactly to the period of the pixels of the workpiece (this means the distance between the pixels) . The distance between the partial beams can be set to a multiple of the pixel period, for example to ten times the period of the pixels. More precise specifications for the zoom unit will be explained in more detail later. Thereafter, a positioning movement carried out via the beam positioning unit can initially result in a further positioning of the partial beams or laser spots on the workpiece. The laser spots can then be processed on the workpiece. The positioning movement and processing movement carried out via the beam positioning unit takes place simultaneously and synchronously for all spots. In particular, those defects can be processed with the device according to the invention which have a similar or identical defect or material deformation. With the machining movement, it is possible to machine individual sections of the workpiece across pixel boundaries.

On the basis of an input data record that reproduces the processing points present or specified on the workpiece or their spatial distribution, the necessary processing path, the number of processing steps, as well as the number and position required for the individual processing steps for processing the processing points present there can be determined from Laser spots or partial beams imaged on the workpiece can be determined. The aforementioned determination can take place, for example, under the premise of the fastest or most efficient possible process management or processing.

As already mentioned at the beginning, the invention is not only directed to the laser processing device, but also to a method for processing predetermined processing points of a workpiece, but using the laser processing device according to the invention.

In a first process step a. As mentioned, a number of processing steps, a relative position of the workpiece to the laser processing device required to carry out the respective processing steps, a processing path comprising the relative positions of the respective processing steps, as well as a number of processing steps based on an input data record relating to the processing points present on the workpiece or their spatial distribution the number and position of partial beams required for the respective processing steps for processing the processing points.

In a further process step b. the workpiece is arranged in a workpiece holder. The workpiece holder can be a component of the laser processing device as such, and the workpiece holder can also be designed as a separate component. In the simplest case, the workpiece holder can be designed in the form of a support plate or a table on which the workpiece can be positioned based on weight force. Other configurations of the workpiece holder are also conceivable, as well as the provision of suitable fastening or positioning means for fastening or positioning the workpiece in the workpiece holder. The workpiece holder can also be an xy table which can be moved in a horizontal plane. Accordingly, the workpiece can be moved over the xy table in a horizontal plane or working plane.

• • das Werkstück relativ zu der Laserbearbeitungsvorrichtung positioniert wird;
• • ein Laserstrahl von der Laserstrahlungsquelle erzeugt und entlang des optischen Pfades in Richtung des Werkstücks ausgesendet wird;
• • der Laserstrahl von der Strahlteilungseinheit in eine Vielzahl von Teilstrahlen aufgeteilt wird, die in einem vorgegebenen räumlichen Pattern verteilt sind;
• • unter Einsatz der Strahlselektionseinheit
  1. i. eine erste Anzahl der Teilstrahlen entlang des optischen Pfades in Richtung des Werkstücks weitergeleitet wird, und
  2. ii. eine zweite Anzahl der Teilstrahlen von dem optischen Pfad abgelenkt wird,
  wobei aus dem räumlichen Pattern der Teilstrahlen in beliebiger räumlicher Kombination Teilstrahlen selektiert und der ersten Anzahl und der zweiten Anzahl zugeordnet werden, und wobei die erste Anzahl der Teilstrahlen zu der Anzahl (A) der in dem jeweiligen Bearbeitungsschritt zur Bearbeitung der Bearbeitungsstellen benötigten Teilstrahlen korrespondiert;
• • unter Einsatz der Strahlpositionierungseinheit eine Anordnung von zu der ersten Anzahl der Teilstrahlen korrespondierenden Laserspots auf dem Werkstück abgebildet und entsprechend der Position der in dem ersten Bearbeitungsschritt zu bearbeitenden Bearbeitungsstellen positioniert wird;
• • gegebenenfalls unter Einsatz der Strahlpositionierungseinheit eine simultan und synchron ausgeführte Bearbeitungsbewegung der Laserspots auf dem Werkstück ausgeführt wird.

In a further process step c. a first processing step is then carried out, wherein

• • the workpiece is positioned relative to the laser processing device;
• • a laser beam is generated by the laser radiation source and emitted along the optical path in the direction of the workpiece;
• • the laser beam is split by the beam splitting unit into a multiplicity of partial beams which are distributed in a predetermined spatial pattern;
• • using the beam selection unit
  1. i. a first number of the partial beams is forwarded along the optical path in the direction of the workpiece, and
  2. ii. a second number of the partial beams are deflected from the optical path,
  where partial beams are selected from the spatial pattern of the partial beams in any spatial combination and assigned to the first number and the second number, and where the first number of partial beams corresponds to the number (A) of partial beams required in the respective processing step for processing the processing points;
• • using the beam positioning unit, an arrangement of laser spots corresponding to the first number of partial beams is imaged on the workpiece and positioned in accordance with the position of the processing points to be processed in the first processing step;
• • if necessary, a simultaneous and synchronous machining movement of the laser spots is carried out on the workpiece using the beam positioning unit.

In the case of processing in point-and-shoot mode, no processing movement of the laser spots has to take place on the workpiece. This is expressed through the aforementioned use of the term “if applicable.

In a further process step d. the in process step c. steps described according to the number of processing steps specified, taking into account the steps in step a. specified conditions repeatedly. The design features described in connection with the laser processing device according to the invention are also to be used as possible advantageous designs of the method according to the invention.

As already mentioned, the device according to the invention comprises a laser radiation source which is set up to generate a laser beam and to emit it along an optical path in the direction of the workpiece. The emitted laser beam can pass through optical functional elements between the laser radiation source and the workpiece, be reflected, refracted, divided or deflected on them. In the present case, the generated and emitted laser beam can be understood to be a continuous laser beam, but in particular a laser pulse.

According to the invention, the device further comprises a beam splitting unit arranged downstream of the laser radiation source in the beam direction. This is set up to split the laser beam into a large number of partial beams which are distributed in a predetermined spatial pattern. In addition, a beam shaping element can be provided between the laser radiation source and the beam splitting unit, with which a plurality of parallel partial beams with a predetermined intensity distribution can be generated from a laser beam with Gaussian intensity distribution in combination with the beam splitting unit on the workpiece, for example a top-hat intensity distribution or an annular intensity distribution.

In this context, the term “beam direction” refers to the course of the laser beam. The specification of the beam splitting unit “downstream” in relation to the laser radiation source means that the beam splitting unit is arranged along the optical path behind the laser radiation source. The laser beam is thus initially generated and only then enters the beam splitting unit or strikes it.

The beam splitting unit can, for example, be a diffractive optical element (DOE). For the relevant details, reference is made to the introductory part of the description. In principle, however, it is also possible to use a “spatial light modulator” known in principle from the prior art as the beam splitting unit, as long as the beam splitting is ensured with the latter. A spatial light modulator is to be understood as an optical component which varies the phase and / or the amplitude of a laser beam locally as a function of the location. An incoming laser beam is phase and / or amplitude modulated by means of the spatial light modulator.

Spatial light modulators for transmission are known from the prior art, which locally generate a phase delay in a laser beam passing through the spatial light modulator. Furthermore, spatial light modulators are known which locally generate an amplitude weakening in a laser beam passing through the spatial light modulator. Both types of spatial light modulators act as diffractive elements, behind which diffraction patterns result, which depend on the exact spatial arrangement of the decelerating or attenuating areas. The diffraction image generated, i.e. the rays of various orders on which the diffraction image is based can also be regarded as partial rays in the context of the present invention. It should be emphasized that it is preferred according to the invention to use a beam splitting unit based on a DOE.

Furthermore, variable spatial light modulators are known from the prior art, in which the intensity distribution of the modulated laser beam resulting on the workpiece can be adjusted electronically. Such variable spatial light modulators can also be based on a locally varying phase delay and / or amplitude attenuation. As a rule, such spatial light modulators are not irradiated, but are used in a reflection configuration. Spatial light modulators which are based on a reflection of laser radiation on a semiconductor surface, in front of which a liquid crystal layer is arranged, may be mentioned as an example at this point. The birefringent properties of the liquid crystal layer can be adjusted locally in a targeted manner, for example by applying an electric field via microstructured electrodes. Corresponding spatial light modulators are sold by Hamamatsu under the name LCOS (“Liquid Crystal on Silicon”) - Spatial Light Modulator. Transmitting variable spatial light modulators are also known; these are sold, for example, by the Jenoptik company under the name “Liquid crystal light modulators Spatial Light Modulator-S”. The diffraction images generated with such variable spatial light modulators can also be regarded as partial beams within the meaning of the invention, but the variant of the design of the beam splitting unit in the form of a diffractive beam splitter described above is to be preferred.

Amplitude-modulated, variable spatial light modulators based on micromechanical micromirror arrays may also be mentioned. The individually controllable micromirrors allow specific spatial areas to be “faded out” from the cross-section of a laser beam. A diffraction image then results from the diffraction of the incident laser radiation on a “grating” in a reflection arrangement. Diffraction images generated in this way can in principle also be viewed as partial beams within the meaning of the present invention.

As already mentioned, the laser processing device proposed by the present invention comprises a beam selection unit. With this, a first number of the partial beams can be passed on or deflected along the optical path in the direction of the workpiece. Furthermore, a second number of partial beams can be deflected out of the optical path, which means that the second number of partial beams does not impinge on the workpiece. The amount of that of the first and second number (i.e. the partial beams diverted in the direction of the workpiece and the partial rays diverted from the optical path) depends on the number of processing points of the workpiece area that lies in the area of the scan field in a certain processing step. If, for example, the beam splitting unit makes it possible in principle to split the laser beam into a 16 by 16 partial beam array and align it to a workpiece, and if there are only four flaws in the area of the workpiece accessible to the scan field, then only four partial beams have to be provided for processing. The excess partial beams can then be deflected out of the optical path with the beam selection unit.

As already mentioned, a further component of the laser processing device according to the invention is a beam positioning unit which is arranged downstream of the beam selection unit in the beam direction and is designed to image laser spots corresponding to the first number of partial beams on the workpiece. Furthermore, the beam positioning unit is set up to move the laser spots simultaneously and synchronously over the workpiece for positioning and processing. The positioning can be upstream of the machining. Both steps can be repeated for the individual processing steps after the workpiece has been positioned relative to the laser processing device. However, it is easily possible to machine a workpiece at a predetermined number of locations without performing a machining movement, e.g. B. in point-and-shoot mode.

The beam positioning unit can be, for example, a galvanometer scanner. Such a scanner can have one or more mirrors, each of which can be rotated about a rotation axis by a defined angle. As a result, the laser beam reflected by the mirrors can be directed as a laser spot within the accessible scan field to a desired location on the workpiece.

The subclaims relate to advantageous configurations and developments of the present invention. The features mentioned in the subclaims can be used in any combination to further develop the device according to the invention and the method according to the invention, insofar as this is technically possible. This also applies if such combinations are not expressly made clear by corresponding references in the claims. In particular, this also applies beyond the category boundaries of the patent claims.

According to a first embodiment of the invention, a first relay unit can be arranged between the beam splitting unit and the beam selection unit, which relay unit is set up to focus the partial beams and align them in parallel. The first relay unit can for example be designed as a single lens, for example as an achromatic lens. In practice it has however, the use of complex lens systems has proven advantageous.

According to a further embodiment of the present invention, a mask can be arranged between the beam splitting unit and the first relay unit, which mask is set up to filter out partial beams of a higher or undesired order. The mask can also be provided and configured to filter out undiffracted components of the laser radiation.

As already mentioned above, the beam splitting unit can be a diffractive optical element (DOE). The DOE can be designed as a rotating plate, for example, which can be controlled via a control unit.

According to a further embodiment of the laser processing device, it can be provided that the beam splitting unit, i.e. the DOE, splits the laser beam into a two-dimensional array of partial beams as a spatial pattern, the two-dimensional array being an equidistant array. To name just two examples (but these are not to be understood as limiting), the beam splitting unit can split an incident laser beam into an array of 18 by 18 or 16 by 16 partial beams. The distance achieved on the workpiece between the associated laser spots of the partial beams can be preset via the beam splitting unit. The partial beams divided by means of the beam splitting unit are all in a fixed angular relationship to one another. Alternatively, the beam splitting unit can also split the laser beam into a one-dimensional array of partial beams, for example 1 × 50).

According to a further advantageous embodiment, it can be provided that a beam shaping element is arranged between the laser radiation source and the beam splitting unit, which is designed to convert a Gaussian intensity distribution of the laser beam into an intensity distribution that differs therefrom, in particular into a top-hat intensity distribution or a ring-shaped intensity distribution. In particular, it can thus be achieved that a top-hat intensity distribution or an annular intensity distribution of the partial beams or laser spots projected onto the workpiece is generated in a workpiece plane.

According to a further embodiment of the laser processing device according to the invention it can be provided that a second relay unit is arranged between the beam selection unit and the beam positioning unit, which is set up to collimate the first number of partial beams so that the collimated partial beams are arranged downstream of the second relay -Unit arranged point converge. As a result, the optical axes of the respective partial beams cross at the point mentioned, the point providing a focal point. The second relay unit can also be designed as a single lens or as a complex lens system. The partial beams can be converged with the second relay unit, which means that they can be deflected by the second relay unit in such a way that they converge on one another. The beam directions are changed in such a way that the distance between the partial beams in the direction perpendicular to an axis belonging to the optical path is reduced to a point of the smallest distance.

According to a further advantageous embodiment of the invention it can be provided that a mask is arranged between the first relay unit and the second relay unit, which mask is set up to filter out partial beams of zero and / or higher order, the mask being in particular can be a static mask.

According to a further embodiment of the laser processing device according to the invention it can be provided that a zoom unit is arranged between the beam selection unit and the second relay unit, which zoom unit is set up to set the alignment or the spacing of the first number of partial beams from one another. The alignment or the setting of the spacing of the partial beams can take place simultaneously. An alignment is in particular the adaptation of the period of the laser spots present on the workpiece to the period of the workpiece, for example a period of the pixels to be processed. In summary, it should be noted that the first relay unit aligns the partial beams parallel to one another. The second relay unit converts the beam offset of the partial beams thus generated into an angle change; this angle change is then converted back into a distance in a focusing unit, which effectively results in the change in the aforementioned spot period.

According to a further embodiment of the laser processing device according to the invention, it can be provided that the partial beams derived from the optical path by the beam selection unit are deflected in the direction of a beam blocking unit, for example along a secondary optical path in which the beam blocking unit is arranged as an immovable unit. The number of partial beams striking the workpiece can be flexibly adjusted via the interaction of the beam selection unit and the beam blocking unit. This relates not only to the number of partial beams, but also to their spatial selection based on one of the Beam splitting unit provided two-dimensional partial beam array. From the latter, the partial beams can be selected in any combination with regard to their position and assigned to the first or the second number of partial beams.

As already mentioned at the beginning, it can be provided according to the invention that, on the basis of an input data record with regard to the processing points present on the workpiece or their spatial distribution, a number of processing steps, a relative position of the workpiece to the laser processing device required to carry out the (respective) processing steps, a processing path comprising the relative positions of the respective processing steps, as well as the number and position of partial beams required for the respective processing steps for processing the processing points is specified. This can be done via a control unit that is either integrated into the laser processing device or is external to it. In the case of external training, a signal and data connection between the control unit and the laser processing device must be guaranteed. The determination of the aforementioned operating parameters depends on the specific pattern of the processing points or the distribution of the processing points on the workpiece to be processed and can vary from workpiece to workpiece. For each individual case, new optimal machining parameters must be calculated.

As already indicated above, it can be provided in a further advantageous embodiment of the invention that the workpiece is arranged on an xy table that can be moved in a horizontal plane, and that the control unit is set up to move the xy table to perform a relative movement of the workpiece to be controlled in relation to the laser processing device. The xy table can have a suitable mechanical movement unit (this can include, for example, an axis system) with which the table can be moved.

1. a. die erste Anzahl und räumliche Anordnung der von der Strahlselektionseinheit in Richtung des Werkstücks weitergeleiteten Teilstrahlen zu ermitteln,
2. b. die zweite Anzahl und räumliche Anordnung der von der Strahlselektionseinheit aus dem optischen Pfad abgeleiteten Teilstrahlen zu ermitteln, und
3. c. einen Positionierungs- und Bearbeitungsweg für eine von der Strahlpositionierungseinheit ausgeführte Positionier- und Bearbeitungsbewegung der ersten Anzahl der Teilstrahlen bzw. den zugehörigen Laserspots auf dem Werkstück zu ermitteln.

According to a further embodiment of the invention, the control unit can be set up for each of the individual processing steps

1. a. determine the first number and spatial arrangement of the partial beams forwarded by the beam selection unit in the direction of the workpiece,
2. b. to determine the second number and spatial arrangement of the partial beams derived from the optical path by the beam selection unit, and
3. c. to determine a positioning and processing path for a positioning and processing movement, executed by the beam positioning unit, of the first number of partial beams or the associated laser spots on the workpiece.

The under the preceding paragraphs a. and b. The conditions described define the shape of a two-dimensional spot array required for processing at a specific position. The number of partial beams directed onto the workpiece or the laser spots imaged thereon, as well as a pattern (or the spatial arrangement or distribution) of the spots depends on the number of processing points on the workpiece or their two-dimensional spatial distribution. According to the invention, the control unit can be set up to control the beam selection unit and the beam positioning unit. Only in this way can the laser processing device according to the under a. to c. are operated.

According to a further embodiment of the invention, a focusing unit can be arranged downstream of the beam positioning unit. This can be set up to focus the first number of partial beams onto the workpiece while forming the laser spots. For example, the focusing unit can be designed as a lens, preferably as an F-theta lens, which is also referred to as a plane field lens. In this context, a lens is also to be understood as a complex lens system composed of several lenses.

According to a further advantageous embodiment of the invention, a pulsed laser beam can be generated with the laser radiation source. Typical pulse repetition rates are in the range between a few Hertz and a few Megahertz. For effective material processing, it has proven to be advantageous if the pulse duration is less than 100 ns, preferably less than 10 ns, in particular less than 1 ns. In this pulse duration range, thermally induced effects predominate in material processing. The pulses can be applied with powers of more than 10 W, even more than 40 W. A power of a few 50 - 500 mW can be present for each Telstrahl

If pulsed laser radiation with a shorter pulse duration is used, effects that are associated with the deposition of comparable very high amounts of energy in a very short time, ie with high peak powers, gain influence. These effects can in particular be sublimation effects in which the material of the workpiece suddenly evaporates locally, ie effects in which material is removed instead of material redistribution. Here, the use of pulsed laser radiation with a pulse duration of less than 100 ps, particularly preferably less than 10 ps and very particularly preferably less than 1 ps, have proven advantageous. In particular, pulse durations in the range of a few hundred femtoseconds up to about 10 ps allow targeted material removal by sublimation. Typical pulse repetition rates are between 50 and 2000 Hz. The pulse energies used in the context of the present invention can be in the range from 5 to 1000 μJ for the laser beam before the beam is split.

Laser radiation sources with even shorter pulse durations that will be available in the future can also be used advantageously in connection with the device according to the invention or the method according to the invention.

However, the use of pulsed laser radiation with pulse durations even longer than the above-mentioned 100 ns can also be useful, for example if certain wavelengths are required for the machining task, or if a slower energy deposition is advantageous, for example to achieve targeted local heating to initiate a local machining reaction, which can also be of a chemical nature, such as initiating a polymerization reaction, and at the same time avoiding premature material removal.

Although the present invention is not limited to the use of a laser with a specific wavelength, the use of a UV laser as the laser radiation source is advantageous, the laser radiation source preferably being a laser beam with a wavelength of 355 nm, 343 nm, 266 nm or 257 nm generated. During the ablating processing of a workpiece with a laser processing device, the wavelength can be selected such that laser radiation is absorbed by the material to be ablated. Laser radiation with wavelengths in the near infrared and VIS range is less suitable for this, unless short pulse durations in the picosecond and femtosecond range are used. The laser radiation source is preferably set up to generate monochromatic laser radiation. Depending on the processing task, broadband laser radiation sources can also be advantageous.

According to a further advantageous embodiment of the laser processing device according to the invention, the device can have a half-wave delay element. This delay element allows the polarization direction of the generated laser radiation to be adjusted.

According to a further advantageous embodiment of the invention, the beam positioning unit can be designed as a mirror scanner, in particular as a galvanometer scanner. Correspondingly, the beam positioning unit can have one or more rotary drives which are set up to move mirrors provided in the beam positioning unit for the targeted deflection and positioning of the partial beams. Galvanometer scanners for use in laser processing devices are well known.

According to a further advantageous embodiment of the invention, the beam selection unit can comprise a mirror arrangement, for example an array of MEMS mirrors or a micromirror array (DMD arrangement). The acronym MEMS stands for micro-electro-mechanical systems. The acronym DMD denotes a "digital micromirror device". Both components are known from the prior art, which is why reference is made at this point to the general technical knowledge. An essential advantage of the invention is associated with the fact that exactly one mirror of the array of MEMS mirrors or of the micromirror array is assigned to each partial beam impinging on the beam selection unit. In accordance with the configurations described, provision can therefore be made for the beam selection unit to be reflective. MEMS mirrors can be operated either resonantly or quasi-statically. Such mirrors are two-dimensional elements for deflecting radiation. Possible scan frequencies range from 0.1 kHz to 50 kHz.

The mirrors arranged in the beam selection unit can be controlled and tilted or moved individually via a control unit in order to be able to deflect each partial beam individually. As already mentioned, a first number of the partial beams can be passed on or deflected along the optical path in the direction of the workpiece, or removed or deflected from the optical path (the partial beams deflected from the optical path do not hit the workpiece) .

It can be provided, for example, that the individual mirrors can assume two positions, in particular an ON position and an OFF position. In the ON position, the mirrors are switched off, for example, whereas in the OFF position the mirrors are deflected by a predetermined angle, for example 10 °, in relation to the ON position. Depending on the position of the mirrors, a partial beam impinging on such a mirror is passed on (deflected) along the optical path or a corresponding beam path, or along an optical secondary path (this deviates from the optical path). A beam blocking unit, for example, can be arranged in the secondary optical path. The partial beams incident there are therefore not in Direction of the workpiece deflected. In summary, it should be subsumed that each mirror is set up to assume an on position and an off position, with a mirror in the on position being set up to deflect a partial beam from the optical path, and one in the Off-position mirror is set up to forward a partial beam in the direction of the workpiece. With the aforementioned mirror arrangement, in contrast to the beam selection known from the prior art, see in particular the US 9,592,570 B2 , - based on a two-dimensional spot or partial beam pattern present after the beam splitting - any partial beams or spots can be selected for forwarding in the direction of the workpiece. From the US 9,592,570 B2 is only known to select individual spot rows or columns. It should also be emphasized that the selection carried out with the beam selection unit proposed here is preferably carried out reflective. Each individual partial beam can be individually switched dynamically and selectively.

Depending on the position of the mirrors, a preconfigured pattern of laser spots or processing spots results on the workpiece. If all mirrors are switched to their ON position, there is a predefined spot array (e.g. a 10 by 10 array), with all grid positions being occupied by a laser spot. The laser spots each have an approximately constant distance. If not all mirrors are in their ON position, a certain number of the grid positions remain spot-free. With such a method, a large number of different configurations of laser spots imaged on the workpiece can consequently be provided.

According to a further advantageous embodiment, it can be provided that the mirrors are at least partially provided with a dielectric coating. Compared to a metallic surface of a mirror, a dielectric coating prevents the mirror from heating up due to residual absorption of the laser radiation striking the mirror. It can be provided that each mirror is coated completely dielectrically or only partially.

As already described above, in an alternative embodiment the beam selection unit can also be designed to be transmittive or absorptive, in particular as at least one blocking element arranged on a chip. Such chips are freely available on the market (see, for example, https://www.preciseley.com/mems-optical-shutter.html). Said blocking element can be moved within a chip plane at least from a first to a second position. In the first position, transmission (that is, passage through) of a partial beam striking the blocking element is enabled. In the second position, however, a partial beam striking the blocking element is prevented from passing through (absorption). The switching of the blocking element can be controlled via a control unit; accordingly, such a chip (or an array of such chips) is also suitable for use with the present invention.

According to a further advantageous embodiment of the invention, it can be provided that the beam selection unit is provided with a cooling unit. The cooling unit can, for example, be based on water cooling, a Peltier element, or air cooling. A combination of the cooling methods mentioned above is also possible. The cooling unit prevents the mirrors arranged in the beam selection unit from heating up due to the impact of the laser radiation. The resulting waste heat as well as the waste heat produced by electronic components of the beam selection unit can be dissipated by means of the cooling unit.

• 1a das Grundprinzip der vorliegenden Erfindung, nämlich eine schematische Ansicht einer von einer Vielzahl von Pixeln bereitgestellten Werkstückoberfläche, wobei eine bestimmte Anzahl der Pixel Bearbeitungsstellen (z.B. Fehlstellen des Displays) sind;
• 1b das Grundprinzip der vorliegenden Erfindung, nämlich eine schematische Ansicht einer zweidimensionalen Laserspotanordnung, die über eine Strahlteilung bereitgestellt wird;
• 1c das Grundprinzip der vorliegenden Erfindung, nämlich die Bearbeitung der Bearbeitungsstellen mit über eine Selektionseinheit selektierten Laserspots;
• 2 den schematischen Aufbau einer Laserbearbeitungsvorrichtung gemäß der Erfindung;
• 3 eine schematische Ansicht zum Funktionsprinzip jener der Laserbearbeitungsvorrichtung zugehörigen Strahlselektionseinheit.
• 4 eine schematische Ansicht zum Funktionsprinzip jener der Laserbearbeitungsvorrichtung zugehörigen Strahlselektionseinheit in einer zweiten Ausführungsform.

Further advantages, refinements and developments related to the laser processing device according to the invention or the method according to the invention are explained in more detail using an exemplary embodiment described below. This is intended to illustrate the invention to the person skilled in the art and to enable him to carry out the invention without, however, restricting the invention. The features described on the basis of the exemplary embodiment can also be used to develop the laser machining device according to the invention as well as the method according to the invention. The exemplary embodiment is explained in more detail with reference to the figures. There shows:

• 1a the basic principle of the present invention, namely a schematic view of a workpiece surface provided by a plurality of pixels, a certain number of the pixels being processing points (for example flaws in the display);
• 1b the basic principle of the present invention, namely a schematic view of a two-dimensional laser spot arrangement which is provided via a beam splitting;
• 1c the basic principle of the present invention, namely the processing of the processing points with laser spots selected via a selection unit;
• 2 the schematic structure of a laser processing device according to the invention;
• 3 a schematic view of the functional principle of the beam selection unit associated with the laser processing device.
• 4th a schematic view of the functional principle of the beam selection unit associated with the laser processing device in a second embodiment.

With the method on which the invention is based, in a workpiece 2 or defects present on an associated surface are processed and / or repaired. In particular, the present invention relates to the repair of displays or display components, for example OLED displays or miniLED displays. Predefined processing points of a workpiece can also be used 2 (eg a certain pattern of processing points) can be processed with the laser processing device according to the invention, for example by way of a LIFT processing. In the following, “processing points” will be referred to in general terms, including both imperfections and other processing points. A laser processing device is used to carry out the method, the technical features and specifications of which are described in more detail below.

As already described at the outset, the laser processing device according to the invention is particularly suitable for processing processing points 1 of a workpiece 2 , e.g. the missing parts of a display. Before going into the details of the laser processing device according to the invention in detail, the basic principle is very general with reference to FIG 1a to 1c explained.

As the 1a reproduces a workpiece to be machined 2 a grid of a multitude of pixels 30th include ( 1 ). The pixels 30th can in turn have sub-structures (not shown). Single or multiple of the pixels 30th can be used as processing centers 1 can be defined (e.g. as defects, e.g. due to local material inhomogeneities, layer thickness deviations, etc.). It can also be with the processing centers 1 be the desired processing positions that are to be subjected to LIFT processing. In the present example the 1a the processing points (to be processed) are marked with a diagonal line through which the pixels 30th illustrative quadrangles. The 1b shows a configuration of laser spots 18th , or a two-dimensional array of three by three laser spots 18th , which consists of a beam splitting of a laser beam 10 with a beam splitting unit 5 (see. 2 ). The main idea of the invention is to use the array of laser spots 18th with a beam selection unit 6th only those laser spots 18th to be selected via a corresponding partial beam selection and on the workpiece 2 map which ones are used to process the existing processing points 1 are necessary, i.e. three laser spots in the present example 18th . Like in the 1c can be reproduced by the three laser spots 18th are directed at the processing points and are subjected to a processing movement. This runs - as illustrated by the arrows - synchronously and simultaneously.

On the workpiece 2 Any pattern of laser spots or processing spots can therefore be mapped (in adaptation to a pattern of processing points or defects). Without selection with the beam selection unit, a predefined spot array (eg a 3 by 3 array) results, with all of the in 1a shown grid locations of the workpiece 2 would be occupied with a laser spot. The laser spots each have an approximately constant distance. Through an adequate selection of the partial beams transmitted in the direction of the workpiece T , a certain number of the grid positions remain spot-free. Only those grid locations or processing points that also have to be processed are thus processed.

The method according to the invention or the laser processing device according to the invention is characterized in that such processing points 1 can be processed simultaneously in a parallelized processing process, in any spatial combination. In relation to the example of the repair of defects, the method described with the present invention is more cost-effective and faster in comparison to repair techniques based on single-beam laser processing.

Like in the 2 reproduced, the proposed by the present invention laser processing apparatus can include a plurality of a laser beam 10 formed partial beams T on the workpiece to be machined 2 project onto the workpiece 2 can therefore be an array of partial beams T be mapped. The number and position that is on the workpiece 2 pictured partial beams T , can be adjusted flexibly. Furthermore, the partial beams T flexibly switchable, ie only individual ones of the partial beams belonging to the array can easily T on the workpiece 2 be judged. With the laser processing device according to the invention it is therefore possible to produce the workpiece 2 selectively at those pixels with laser radiation (or those from the partial beams T trained laser spots) at which the processing points 1 are trained. In the case of a defect repair, for example at these processing points 1 Any excess display material that is present can be ablated by laser processing. It can therefore be used both within a specified scan area (thus one of the on the workpiece 2 projected partial beams T This means the clamped processing area), as well as processing points across this scan area 1 of the workpiece 2 to be edited. The latter is in particular due to a relative displacement of the workpiece 2 possible in relation to the positionally fixed laser processing device.

At this point it should be emphasized that with the method according to the invention or the device according to the invention, workpieces 2 can be processed in different ways, so the invention is not limited to use in the repair of display defects. In principle, the invention can be used to repair defects in a wide variety of flat products as long as the surface can be ablated by means of the laser radiation used. Especially with workpieces 2 The method according to the invention or the laser processing device according to the invention can be used on the basis of organic materials or plastics. The method according to the invention and the device according to the invention can also be used to machine a workpiece 2 can be used by way of a LIFT procedure.

The distance D2 the one on the workpiece 2 The laser spots shown can be adjusted flexibly. The size of the distance can vary D2 according to the distance between the imperfections 1 measured on the workpiece. This is explained below.

In the 2 the schematic structure of the laser processing device according to the invention is shown. The representation there is a schematic illustration, which means that even if the representation is able to convey that, for example, the partial beams T through the beam selection unit 6th pass through, the beam selection unit 6th is easily - and even preferably - reflective. From the figurative representation of the 2 no information can therefore be derived about the specific functional design of the components. The individual components of the laser processing device can be designed both transmissive and reflective.

The laser processing device can initially hold a workpiece 40 for holding or positioning a workpiece 2 include. The workpiece holder 40 can be designed in the form of an xy table that can be moved in a horizontal plane. The positioning of the workpiece 2 in or on the workpiece holder 40 can be based on weight or using suitable fastening or positioning means (not shown). The workpiece holder 40 can also be arranged externally to the laser processing device.

The laser processing device initially comprises a laser radiation source 3 with which a laser beam 10 generated and along an optical path 4th towards the workpiece 2 is emitted, especially in the form of laser pulses. The laser radiation source 3 is a beam splitting unit in the beam direction 5 subordinate. The beam splitting unit 5 is set up to use the laser beam 10 into a multitude of partial beams T split up. With the beam splitting unit 5 it can be a - known per se - diffractive optical element (DOE). Already with the beam splitting unit 5 can be the number of partial beams T can be preset. Also a coarse adjustment in one plane of the workpiece 2 existing distances between the laser spots of the partial beams T , can already be done with the beam splitting unit 5 to adjust. With the beam splitting unit 6th lets a laser beam 10 split into partial beams that form a two-dimensional spatial pattern of laser spots 18th provide.

In relation to the beam path, it is arranged downstream of the beam splitting unit 5 a mask 8th provided with which undesired partial beams T of higher order can be filtered out. The mask is an optical mask. Downstream of the mask 8th can - as in the 2 reproduced - a first relay unit 7th be provided. The relay unit 7th is set up to work on the relay unit 7th incident partial rays T (These are the ones not with the mask 8th filtered out partial beams T ) to focus and align in parallel. At the relay unit 7th it can be a single lens (i.e. the relay unit 7th can be designed as an achromatic lens, for example), or around a complex lens system.

Downstream of the relay unit 7th is a beam selection unit 6th provided, which is set up to have a first number A1 of the partial beams T along the optical path 4th in the direction of the workpiece to be machined 2 forward or deflect. Furthermore, there is the beam selection unit 6th set up a second number A2 of the partial beams T from the optical path 4th distract. The deflection can take place in the direction of an optical secondary path (not shown), for example in the direction of a beam blocking unit 13 ( 3 ).

According to a first embodiment, the beam selection unit 6th a mirror assembly 15th comprise that of an array of individual mirrors 16 is composed. By the mirrors 16 it can be a MEMS mirror or a micromirror. According to the invention, it is provided that each point to the beam selection unit 6th incident partial beam T to a maximum or exactly one mirror 16 hits. The mirror 16 can be controlled and tilted or moved individually via a control unit, thus around each partial beam T individually to be able to distract. As already mentioned, there can be a certain number A1 of the partial beams T along the optical path 4th towards the workpiece 2 forwarded or deflected, or from the optical path 4th removed.

Like in the 3 The mirrors can be schematically illustrated 16 for example, take two positions, in particular an ON position 100 and an OFF position 200 . In the ON position 100 are the mirrors 16 for example switched off, in the OFF position 200 on the other hand are the mirrors 16 by a predetermined angle, for example 10 °, with respect to the ON position 100 deflected. Depending on the position of the mirror 16 becomes one on such a mirror 16 incident partial beam T along the optical path 4th or a corresponding beam path forwarded (deflected) or along an optical secondary path (this deviates from the optical path 4th from). A static beam blocking unit, for example, can be used in the secondary optical path 13 be arranged. The partial rays impinging there T so are not in the direction of the workpiece 2 distracted (in the 3 are those in the direction of the beam blocking unit 13 derived rays shown in dashed lines). The ON position 100 thus leads to a deflection of the partial beams T towards the beam blocking unit 13 while the OFF position 200 to forward the partial beams T along the optical path 4th towards the workpiece 2 leads.

Depending on the position of the mirror 16 results on the workpiece 2 a pre-configured pattern of laser spots or processing spots. Are all mirrors 16 in their ON position 100 switched, a predefined spot array results (eg a 10 by 10 array), with all grid positions being occupied by a laser spot. The laser spots each have an approximately constant distance. Not all mirrors are in place 16 in their ON position 100 , so a certain number of the grid locations remain spot-free. With such a method, a variety of different configurations of on the workpiece 2 shown laser spots are provided.

As already described above, the beam selection unit 6th In an alternative embodiment, it can also be designed to be transmittive or absorptive ( 4a , 4b) , especially as at least one on a chip 19th arranged blocking element 13 . Such chips are freely available on the market (see, for example, https://www.preciseley.com/mems-optical-shutter.html). Said blocking element 13 is movable within a chip plane at least from a first to a second position. In the first position ( 4a) is a transmission (that is, a passage through) one onto the blocking element 13 incident partial beam T enables. In the second position (cf. 4b) on the other hand there is a passage of one on the blocking element 13 incident partial beam T denied (absorption). Switching the blocking element 13 can be controlled via a control unit, such a chip is also suitable 19th (or an array of such chips) for use with the present invention.

Another mask 17th can be between the first relay unit 7th and the second relay unit 11 be provided. The mask 17th can in particular in front of the beam selection unit 6th arranged and provided for filtering out higher orders and the zero order, cf. the representation after 2 .

Again 2 can also be seen, downstream of the beam selection unit 6th a zoom unit 12th be provided. The zoom unit can be set up for the partial beams T simultaneously adjust in their orientation or inclination and their distance relative to one another. The effect via the zoom unit has a corresponding effect 12th performed adjustment of the partial beams T indirectly also on the alignment and the distance of the on the workpiece 2 projected laser spots. Like in the 2 A distance between the partial beams can be shown D1 as well as one on the workpiece 2 present distance D2 the laser spots via the zoom unit 12th to adjust.

Downstream of the zoom unit 12th is a second relay unit 11 arranged. The second relay unit 11 is set up to do the first number A1 of the partial beams T to collimate so that the collimated partial beams T in a downstream of the second relay unit 11 arranged point 50 (a focal point) converge. In fact, a bundle of partial beams is brought together in the focal point. Even with the second relay unit 11 it can - as with the first relay unit 7th - be a single lens or a complex lens system.

The laser processing device further comprises a beam positioning unit 9 , which can be, for example, a galvanometer scanner which is set up to add to the first number A1 of the partial beams T corresponding laser spots on the workpiece 2 map. Depending on the beam selection unit 6th set pattern, becomes a defined spot pattern - or an arrangement of partial beams T on the workpiece 2 projected. In accordance with the present spot pattern, the beam positioning unit 9 both a simultaneous and synchronous positioning movement on the workpiece 2 projected laser spots are executed, as well as a simultaneous and synchronous execution Machining movement. The positioning movement can be carried out within one via the beam positioning unit 9 accessible scan area. Sub-structures of individual pixels can also be processed using the processing movement described.

With regard to the machining method also proposed by the invention, it should be noted that there is a relative displacement between the workpiece 2 and laser processing device a specific processing point of the workpiece 2 can be controlled, the scan field is thus positioned in a certain sub-area of the workpiece surface. Corresponding to that in this part of the workpiece 2 present distribution of processing points 1 or the processing point pattern, processing adapted to this processing point distribution is carried out. This means that the number of times on the workpiece 2 incident partial rays T or the associated laser spots to the number of processing points present in the section to be processed 1 is adjusted. The spatial arrangement of the laser spots is also determined 18th the spatial distribution of processing points in the respective section of the workpiece 2 customized. The setting of the number and spatial arrangement of the partial beams T or the associated laser spots 18th can be done via a control unit that works with the beam selection unit 6th , the zoom unit 12th and the beam positioning unit 9 can be in a signal and data connection. Furthermore, the control unit can also use the beam splitting unit 5 are in a signal and data connection.

Part of the beam positioning unit 9 can also have a focusing unit 14th be that of the partial beams deflected by the galvanometer scanner T on the workpiece 2 focused. Thereby the laser spots 18th of the partial beams T (according to the set spot pattern) on the workpiece 2 pictured.

List of reference symbols

1

Processing point

2

workpiece

3

Laser radiation source

4th

optical path

5

Beam splitting unit

6th

Beam selection unit

7th

first relay unit

8th

mask

9

Beam positioning unit

10

laser beam

11

second relay unit

12

Zoom unit

13

Beam blocking unit

14th

Focusing unit, F-theta lens

15th

Mirror arrangement

16

mirror

17th

mask

18th

Laser spot

19th

chip

30th

pixel

40

Workpiece holder

100

ON position

200

OFF position

T

Partial beam

A1

first number

A2

second number

D1

distance

D2

distance

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 9592570 B2 [0003, 0061]

Claims (33)

Laser processing device, in particular for processing predetermined processing points (1) of a workpiece (2), comprising a. a laser radiation source (3) which is set up to generate a laser beam (10) and to emit it along an optical path (4) in the direction of the workpiece (2); b. a beam splitting unit (5) arranged downstream of the laser radiation source (3) in the beam direction, which is set up to split the laser beam (10) into a plurality of partial beams (T) which are distributed in a predetermined spatial pattern; c. a beam selection unit (6) arranged downstream of the beam splitting unit (5) in the beam direction, which is set up to • Forward a first number (A1) of the partial beams (T) along the optical path (4) in the direction of the workpiece (2), • deflect a second number (A2) of the partial beams (T) from the optical path (4), the beam selection unit (6) also being set up to add partial beams (T) from the spatial pattern of the partial beams (T) in any spatial combination select and assign to the first number (A1) and the second number (A2); d. a beam positioning unit (9) arranged downstream of the beam selection unit (6) in the beam direction, which is set up to image laser spots (18) corresponding to the first number (A1) of partial beams (T) on the workpiece (2), and is also set up to: to move the laser spots (18) simultaneously and synchronously over the workpiece (2) for positioning and / or processing, if necessary. Laser processing device according to Claim 1 , characterized by a first relay unit (7) arranged between the beam splitting unit (5) and the beam selection unit (6), which relay unit is set up to focus the partial beams (T) and align them in parallel. Laser processing device according to one of the Claims 1 or 2 , characterized by a mask (8) which is arranged between the beam splitting unit (5) and the first relay unit (7) and is set up to filter out partial beams (T) of a higher order. Laser processing device according to one of the preceding claims, characterized in that the beam splitting unit (5) is a diffractive optical element. Laser processing device according to one of the preceding claims, characterized in that a beam shaping element is arranged between the laser radiation source (3) and the beam splitting unit (5), which is set up to convert a Gaussian intensity distribution of the laser beam (10) into an intensity distribution deviating therefrom, in particular into a top-hat intensity distribution or a ring-shaped intensity distribution. Laser processing device according to Claim 4 , characterized in that the beam splitting unit (5) is set up to split the laser beam (10) into a two-dimensional array of partial beams (T) as a spatial pattern, the two-dimensional array being an equidistant array. Laser processing device according to one of the preceding claims, characterized in that a second relay unit (11) is arranged between the beam selection unit (6) and the beam positioning unit (9) which is set up to transmit the first number (A1) of partial beams (T) to collimate so that the collimated partial beams (T) converge in a point (50) arranged downstream of the second relay unit. Laser processing device according to one of the preceding claims, characterized by a mask (17) which is arranged between the first relay unit (7) and the second relay unit (11) and is set up for partial beams (T) of the zeroth and / or higher order filter out, the mask (17) being in particular a static mask. Laser processing device according to one of the preceding claims, characterized by a zoom unit (12) which is arranged between the beam selection unit (6) and the second relay unit (11) and is set up to determine the alignment or the distance (D1) of the first number (A1) of the partial beams (T). Laser processing device according to Claim 9 , characterized in that the alignment or the distance (D2) of the partial beams (T) imaged on the workpiece (2) or the laser spots (18) associated with the partial beams (T) can be set indirectly via the zoom unit (12) is. Laser processing device according to one of the preceding claims, characterized in that the partial beams (T) derived from the optical path (4) by the beam selection unit (6) are deflected in the direction of a beam blocking unit (13). Laser processing device according to one of the preceding claims, characterized in that the partial beams (T) derived from the beam selection unit (6) from the optical path (4) can be derived along a minor optical path. Laser processing device according to Claim 1 , characterized by a control unit which is set up to, on the basis of an input data record with regard to the processing points (1) present on the workpiece (2) or their spatial distribution, a number of processing steps, a relative position of the required to carry out the respective processing steps Workpiece (2) to the laser processing device, a processing path including the relative positions of the respective processing steps, as well as the number (A) and position of partial beams (T) required for the respective processing steps for processing the processing points (1). Laser processing device according to Claim 13 , characterized in that the workpiece (2) is arranged on an xy table that can be moved in a horizontal plane, and that the control unit is set up to control the xy table for executing a relative movement of the workpiece (2) in relation to the laser processing device. Laser processing device according to Claim 13 or 14th , characterized in that the control unit is set up to each a. to determine the first number (A1) and spatial arrangement of the partial beams (T) forwarded by the beam selection unit (6) in the direction of the workpiece (2), b. to determine the second number (A2) and spatial arrangement of the partial beams (T) derived from the optical path (4) by the beam selection unit (6), and c. to determine a positioning and processing path for a positioning and processing movement of the first number (A1) of partial beams (T) or the associated laser spots on the workpiece (2) carried out by the beam positioning unit (9). Laser processing device according to one of the preceding claims, characterized in that the control unit is set up to control the beam selection unit (6) and the beam positioning unit (9). Laser processing device according to one of the preceding claims, characterized by a focusing unit (14) which is arranged downstream of the beam positioning unit (9) and is set up to direct the first number (A1) of partial beams (T) onto the workpiece (2) while forming the laser spots ( 18) to focus. Laser processing device according to Claim 17 , characterized in that the focusing unit (14) is an F-theta lens. Laser processing device according to one of the preceding claims, characterized in that the laser radiation source (3) is set up to generate a pulsed laser beam (10). Laser processing device according to one of the preceding claims, characterized in that the laser radiation source (3) is a UV laser, the UV laser in particular generating a laser beam (10) with a wavelength of 355 nm, 343 nm, 266 nm or 257 nm. Laser processing device according to one of the preceding claims, characterized in that the beam positioning unit (9) is designed as a mirror scanner, in particular as a galvanometer scanner. Laser processing device according to one of the preceding claims, characterized in that the beam selection unit (6) comprises a mirror arrangement (15). Laser processing device according to Claim 22 , characterized in that the mirror arrangement (15) comprises an array of MEMS mirrors or a micromirror array. Laser processing device according to Claim 23 , characterized in that exactly one mirror (16) of the array of MEMS mirrors or of the micromirror array is assigned to each partial beam (T) impinging on the beam selection unit (6). Laser processing device according to Claim 24 , characterized in that each mirror (16) is set up to assume an on position (100) and an off position (200), a mirror (16) in the on position (100) being set up for this purpose to deflect a partial beam (T) out of the optical path (4), and wherein a mirror (16) located in the off position (200) is set up to forward a partial beam (T) in the direction of the workpiece (2). Laser processing device according to Claim 24 , characterized in that the mirrors (16) are at least partially provided with a dielectric coating. Laser processing device according to Claim 22 , characterized in that the beam selection unit (6) is reflective. Laser processing device according to one of the preceding claims, characterized in that the beam selection unit (6) is designed to be transmissive or absorptive. Laser processing device according to Claim 28 , characterized in that the beam selection unit (6) is designed as at least one blocking element arranged on a chip, the at least one blocking element being movable within a chip plane at least from a first to a second position, with a transmission of one to the Blocking element impinging partial beam (T) is enabled and wherein in the second position a passage of a partial beam (T) impinging on the blocking element is prevented. Method for processing predetermined processing points (1) of a workpiece (2) using a device according to the Claim 1 , comprising at least the following steps: b. On the basis of an input data record with regard to the processing points (1) present on the workpiece (2) or their spatial distribution, a number of processing steps, a relative position of the workpiece (2) to the laser processing device required to carry out the respective processing steps, the relative positions of the Processing path comprising the respective processing steps as well as the number (A) and position of partial beams (T) required for the respective processing steps for processing the processing points (1); c. the workpiece (2) is arranged in a workpiece holder; d. a first machining step is carried out, wherein • the workpiece (2) is positioned relative to the laser machining device; • a laser beam (10) is generated by the laser radiation source (3) and emitted along the optical path (4) in the direction of the workpiece (2); • the laser beam (10) is split by the beam splitting unit (5) into a multiplicity of partial beams (T) which are distributed in a predetermined spatial pattern; • using the beam selection unit (6) i. a first number (A1) of the partial beams (T) is forwarded along the optical path (4) in the direction of the workpiece (2), and ii. a second number (A2) of the partial beams (T) is deflected from the optical path (4), partial beams (T) being selected from the spatial pattern of the partial beams (T) in any spatial combination and the first number (A1) and the second Number (A2) are assigned, and the first number (A1) of partial beams corresponds to the number (A) of partial beams (T) required in the respective processing step for processing the processing points (1); • using the beam positioning unit (9) an arrangement of laser spots corresponding to the first number (A1) of partial beams (T) is imaged on the workpiece (2) and positioned according to the position of the processing points to be processed in the first processing step; • if necessary using the beam positioning unit (9), a simultaneous and synchronous processing movement of the laser spots is carried out on the workpiece (2); e. in the process step c. The steps described are carried out according to the number of processing steps specified, taking into account the steps in step a. specified conditions repeatedly. Procedure according to Claim 30 , characterized in that the method using a device according to one of Claims 2 to 29 is performed. Procedure according to Claim 30 or 31 , characterized in that the workpiece (2) is subjected to a positioning relative to the laser processing device for the execution of a respective processing step via a movement mediated by the xy table. Method according to one of the Claims 30 to 32 , characterized in that the laser spots are subjected to positioning via the zoom unit (12) and / or the beam positioning unit (9).

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